Process for the metallization of porcelain or glass



Patented 0a. 27, 1925.

UNITED STATES PATENT orrica.

AIPHONSE FLORENT nIJssnn, or HEERLEN, NETHERLANDS...

rnocnss' non THE rrnrnnmzarlon or PORCELAIN on GLASS.

No Drawing.

To all whom it may concern:

Be it known that I, 'ALPHONSE FLoRnNT EIJSSEN, a subject of the Queen ofHolland, residing at Heerlen, Province of Limburg, Kingdom of theNetherlands, have invented an. Improved Process for the Metallization ofPorcelain or Glass, of which the fola coatin of alkali silicate and thenwith a coating containing KCN,NH,F1 and AgCl.

This coating is reduced with hydrazine, the reduction of the silverbeing completed by brushing with a metal brush (of copper, brass, iron,zinc, etc.).

According to the invention in order to obtain a metallized conductingsurface without using a silver salt, glycerol is rubbed with a brush ofbrass r similar material on to the surface of the object to bemetallized, by which treatment a deposit of. brass is obtained on the,porcelain or 'glass, which is made conducting in this manner. A littlenitrate of silver may be added to theglycerol when silver is, desired inthe deposit. Generally however this is notrequired. In lieu of glycerolalso other viscous polyvalent alcohols may beused such as glycol and thelike. I In order to cover such a metallized surface with more metal, itis connected by means of a copper wire to the negative pole of a dynamoor a galvanic battery, the positive pole of which is connected to acopper plate which is placed with'the object to be metallized in asolution of e. g.

1 liter water.

200 grams sulphate of copper.

20 grams sulphuric acid of 66 B.

Then an electric'current is passed of a density of about 5 amperes persquare decimeter of the surface to be metall zed.

For applying the invention, the surface to' be treated must first bedulled, -e. g. by means of a sand blast machineiworkingat a pressureofper sq. cm. and fine white sand. The'dulled surface is rubbed with avery small quantity of glycerol using a brass brush. It will be observedimmediately that a very adherent deposit of brass Application filedDecember 12, 1924. Serial No. 755,580.

is obtained on the porcelainor glass, and care must be taken torub thedulled glass with the brass brush until the surface is quite dry so thatit has a dark green appearance. If too much glycerol is used goodadhesion of the metal to the treated object cannot be obtained.

, After this treatment, the rubbed surface of the object has wrappedround it or ap plied'to it by a copper wire which is connected to thenegative pole of a source of current, the positive pole of which isconnected to a copper plate immersed in the same bath. as the object'tobe metallized, said bath being filled with a solution of copper sulphateof about the above mentioned composition. The bath is electrolyzed at atemperature of 14;"20 G. and a current density of 5 amp. per squaredecimeter of the rubbed surface. After a few minutes it is observed thatthe rubbed part is covered with a layer offcopper. When the objects aremetallized sufficiently, they. are removed from the bath and polished.

They may be afterwards covered with sllver or nickel in the usual way.

In the manner described one may e. g.

metallize the outside of porcelain kettles.

Such kettles have the advantage that they do not burst, are less subjectto breakage and remain hot for a longer period than ordinary porcelainkettles. Porcelain cans for coffee, tea or milk may be treated accordingto the invention to protect them against breakage. Such metallizedobjects of glass orporcelain compared with similar metal objects havethe advantage that they do not leave a metal taste when in use and canbe cleaned very easily. They have therefore hygienic advantages. sibleto use the invention for ornamental purposes. I

What Iv claim is:

1. A process for metallizing a dull surface of non-conducting hardmaterial comprising rubbing the surface with a very smallquantity of aviscous polyvalent alcohol by means of a metal brush and then depositingelectrolytically a further -meta1 coating.

2. In a process for metallizing a dull sur-- face of non-conducting hardmaterial the step of rubbing the surface with a very small quantity ofglycerol by means of a metal brush.

3. In a process for metallizing a dull sur- 6 It 1s, also posface ofnon-conducting hard material the step of rubbing the surface with a verysmall quantity of. glycerol by means of a brass brush.

4. A process according to claim in which nitrate of silver is added tothe glycerol. 5. A process for metallizing objects of nnglazed porcelaincomprising rubbing the surface to be metallized with avery smallquantity of glycerol by means of a brass 10 brush, connecting theobjectby means of a copper wire to the negative pole of an elec- 'lricmachine. while the ()lJJGCt 1S immersed ALPHON bE FLOREN EIJ SSEN.

